package array;

public class Array<E> {
    private E[] data;
    private int size;

    public Array(E[] arr) {
        data = (E[]) new Object[arr.length];
        for (int i = 0; i < arr.length; i++) {
            data[i] = arr[i];
        }
        size = arr.length;
    }

    public Array(int capacity) {
        data = (E[]) new Object[capacity];
        size = 0;
    }

    public Array() {
        this(10);
    }

    public int getSize() {
        return size;
    }

    public int getCapacity() {
        return data.length;
    }

    public boolean isEmpty() {
        return size == 0;
    }

    public void addLast(E e) {
		/* if (size == data.length){
			throw new IllegalArgumentException("参数错误,数组已满");
		}
		data[size] = e;
		size++;*/
        add(size, e);
    }

    public void addFirst(E e) {
        add(0, e);
    }

    public void add(int index, E e) {
        if (index < 0 || index > size) {
            throw new IllegalArgumentException("add 参数错误,index < 0 || index > size");
        }
        if (size == data.length) {
            resize(2 * data.length);
        }

        for (int i = size - 1; i >= index; i--) {
            data[i + 1] = data[i];
        }
        data[index] = e;
        size++;
    }

    private void resize(int newCapacity) {
        E[] newData = (E[])new Object[newCapacity];
        for (int i = 0; i < size; i++) {
            newData[i] = data[i];
        }
        data = newData;
    }

    public E get(int index) {
        if (index < 0 || index > size) {
            throw new IllegalArgumentException("get 参数错误,index < 0 || index > size");
        }
        return data[index];
    }
    public E getLast(){
        return get(size - 1);
    }
    public E getFirst(){
        return get(0);
    }

    public void set(int index, E e) {
        if (index < 0 || index > size) {
            throw new IllegalArgumentException("set 参数错误,index < 0 || index > size");
        }
        data[index] = e;
    }

    public boolean contains(E e) {
        for (int i = 0; i < size; i++) {
            if (data[i].equals(e)) {
                return true;
            }
        }
        return false;
    }

    public int find(E e) {
        for (int i = 0; i < size; i++) {
            if (data[i].equals(e)) {
                return i;
            }
        }
        return -1;
    }

    public E remove(int index){
        if (index < 0 || index > size) {
            throw new IllegalArgumentException("set 参数错误,index < 0 || index > size");
        }
        E ret = data[index];
        for (int i = index + 1; i < size; i++) {
            data[i-1] = data[i];
        }
        size--;
        data[size] = null;
        if(size == data.length / 4 && data.length / 2 != 0){//采用lazy策略
            resize(data.length / 2);
        }
        return ret;
    }

    public E removeFirst(){
        return remove(0);
    }

    public E removeLast(){
        return remove(size-1);
    }
    public void removeElement(E e){
        int index = find(e);
        if(index != -1){
            remove(index);
        }
    }

    public void swap(int i,int j){
        if(i < 0 || i >= size || j < 0 || j >= size) {
            throw new IllegalArgumentException("Index is illegel");
        }

        E t = data[i];
        data[i] = data[j];
        data[j] = t;
    }

    @Override
    public String toString() {
        StringBuilder res = new StringBuilder();
        res.append(String.format("array.Array: size = %d, capacity = %d\n", size, data.length));
        res.append("[");
        for (int i = 0; i < size; i++) {
            res.append(data[i]);
            if (i != size - 1) {
                res.append(",");
            }
        }
        res.append("]");
        return res.toString();
    }

    public static void main(String[] args) {
        Array<Integer> arr = new Array<>();
        for (int i = 0; i < 10; i++) {
            arr.addLast(i);
        }
        System.out.println(arr);

        arr.add(1,100);
        System.out.println(arr);

        arr.addFirst(-1);
        System.out.println(arr);

        arr.remove(2);
        System.out.println(arr);
        arr.removeElement(4);
        System.out.println(arr);

        arr.removeFirst();
        System.out.println(arr);
    }
}
